The present invention relates to the splitting or other separation of optical fibers and, more particularly, to an apparatus and method for splitting or otherwise separating optical fibers.
Optical fibers must frequently be separated, branched, or otherwise redirected since not all optical fibers of a fiber optic cable will terminate at the same location. For example, a fiber optic cable may include optical fibers that must be directed to a plurality of different homes, businesses, offices or the like. Oftentimes, splice closures, patch closures and other types of closures are utilized to facilitate the splitting and redirection of one or more optical fibers from a fiber optic cable, while also serving to protect the optical fibers from environmental degradation and from mechanical stress and strain.
In a typical closure, a number of the optical fibers extend through the closure without being cut and spliced or otherwise connected. These optical fibers are generally termed express fibers. One or more of the optical fibers are separated from the express fibers, however, cut and redirected to a splice tray, a coupler tray, a connector panel or the like. The optical fibers that have been separated from the express fibers can then be spliced, coupled or otherwise connected to other optical fibers to be directed to a different location than the express fibers. In one common example in which a fiber optic feeder cable is received within a closure, a plurality of optical fibers are separated from the express fibers of the fiber optic feeder cable and are spliced to a corresponding plurality of optical fibers of fiber optic drop cables that extend from the closure to a home, a business or the like.
Even within a closure, however, care must be taken to separate the optical fibers from the express fibers without damaging the optical fibers. For example, if the optical fibers that are separated from the express fibers are bent too sharply, the optical fibers can be broken or otherwise physically damaged, such as by creating microfractures, whereby the optical fibers no longer properly transmit optical signals.
Moreover, in the common situation in which a plurality of optical fibers are to be separated from a fiber optic feeder cable in a taut sheath application, a section of the sheath is removed to expose the buffer tube(s) or, in some instances, the optical fibers themselves. In instances in which the optical fibers to be separated are disposed within a buffer tube, the buffer tube is also removed to thereby expose the optical fibers. The optical fibers to be separated are then cut and redirected to a splice tray, a coupler tray, a connector panel or the like. Due to the removal of the sheath and, in some instances the buffer tube(s) of the fiber optic feeder cable, the optical fibers to be separated are exposed for only a relatively limited length, generally about 18 to 24 inches in a typical closure. Thus, the optical fibers to be separated from the express fibers of the fiber optic feeder cable must be routed to the splice tray, coupler tray, connector panel or the like in a relatively direct manner, while still taking care not to excessively bend or otherwise damage the optical fibers.
While bare optical fibers are commonly separated and routed within a closure, spiral wrap tubing can be wrapped about the optical fibers to protect the optical fibers from excessive bending or other physical damage. As will be apparent, however, the wrapping of spiral wrap tubing about the optical fibers requires a field technician to expend additional time during the configuration of the closure. The optical fibers that are separated from the express optical fibers can also be disposed within transport tubes that serve at least partially to protect the optical fibers from being bent excessively or otherwise physically damaged. Unfortunately, neither the spiral wrap tubing nor the transport tubes completely protect the optical fibers from excessive bending or other types of physical damage, especially at the transition point at which the optical fibers are split or otherwise separated.
A funnel kit has been developed by Raychem Corporation for splitting optical fibers and for protecting the optical fibers at the point of separation. The funnel kit defines an input port and an opposed output port. The funnel tapers radially outwardly in a direction from the input port to the output port such that the output port is substantially larger in diameter than the input port. Moreover, the funnel kit includes an insert that is disposed within the output port and that defines a plurality of passageways therethrough. As such, the funnel kit can be mounted upon a plurality of optical fibers, such as the optical fibers of a fiber optic feeder cable, and the optical fibers can be slit or otherwise separated into different groups that extend through respective passageways defined by the insert. For example, express fibers can extend through a passageway that is coaxial with the longitudinal axis of the funnel, while the optical fibers that are to be separated from the express fibers can be directed to other passageways. Transport tubes can also be inserted into the passageways to protect the optical fibers upon their exit from the funnel kit. While effective for protecting the optical fibers at their point of separation, the funnel kit requires that each of the optical fibers, including the express fibers, be cut before being inserted through the funnel. As will be apparent, the cutting and subsequent splicing of each of the optical fibers will increase the time required for a field technician to properly route the optical fibers and furthermore may somewhat attenuate the optical signals propagating along the optical fibers.
Thus, it would be desirable to develop improved techniques for splitting or otherwise separating and routing optical fibers in a manner that protects the optical fibers from being bent excessively and from other physical damage. In addition, it would be desirable for methods to be developed for splitting or otherwise separating and routing optical fibers that do not require each of the optical fibers, especially the express fibers, to be cut, thereby reducing the time required for a field technician to configure a closure.
An apparatus and method for splitting or otherwise separating and routing optical fibers are therefore provided in which a splitter housing is mounted upon a plurality of optical fibers without having to cut all of the optical fibers, and in particular, without having the cut the express fibers. The splitter housing is adapted to be readily mounted upon the optical fibers such that the time required for a field technician to configure a closure utilizing the apparatus and method of the present invention is advantageously reduced. Moreover, the apparatus and method of the present invention protects the optical fibers at the point of splitting or otherwise separating such that the optical fibers are not bent excessively and are protected from other physical damage.
According to one embodiment, an apparatus for splitting optical fibers is provided that includes splitter housing extending lengthwise between opposed first and second ends. The splitter housing defines an input port, proximate the first end, for receiving a plurality of optical fibers. The splitter housing also defines primary and secondary output ports, proximate the opposed second end, through which the plurality of optical fibers exit the splitter housing.
The splitter housing includes first and second halves. Each half of the splitter housing extends lengthwise between the opposed first and second ends. Each half of the splitter housing defines at least a portion of the input port and at least one and, more typically, both of the output ports. The first and second halves of the splitter housing of this embodiment are preferably at least partially separable. As such, the splitter housing can be mounted upon the plurality of optical fibers without having to cut all of the optical fibers. In particular, the splitter housing can be installed around the optical fibers without having to cut the express fibers, thereby simplifying the installation process and reducing the time required by a field technician to configure the closure.
The apparatus for splitting optical fibers may also include a separation element disposed within the splitter housing proximate the secondary output port. The separation element defines a plurality of channels. The optical fibers that exit the secondary output port are directed through respective channels of the separation element to separate the optical fibers. Each channel defined by the separation element extends in a lengthwise direction and defines a lateral cross-sectional area that increases in a direction towards the secondary output port. The apparatus for splitting optical fibers can further include a plurality of transport tubes that are partially inserted into respective channels defined by the separation element. As a result of the tapered shape of each channel, the transport tubes can be engaged within respective channels defined by the separation element.
The apparatus for splitting optical fibers may also include an adapter element disposed within the splitter housing proximate the input port for facilitating mounting the splitter housing upon different types of fiber optic cables. Further, the apparatus for splitting optical fibers may include a fiber retainer disposed within the splitter housing proximate the secondary output port for engaging at least some of the optical fibers that exit through the secondary output port. The fiber retainer can therefore retain those optical fibers within the splitter housing while the first and second halves of the splitter housing are closed, thereby preventing the optical fibers from being crushed between the first and second halves of the splitter housing. Each half of the splitter housing may also include corresponding latches such that the first and second halves of the splitter housing are secured together in the closed position.
According to another aspect to the present invention, the apparatus for splitting optical fibers includes an inline portion and a branch portion. The inline portion defines the input port at one end for receiving the plurality of optical fibers and the primary output port at the opposed end through which at least one optical fiber exits. The inline portion is configured such that the input port and the primary output port are coaxial. In the typical embodiment in which the express fibers extend through the inline portion, the express fibers therefore need not be bent. On the other hand, the branch portion extends outwardly from the inline portion adjacent one end to the secondary output port at the opposed end. The branch portion is in communication with the inline portion such that at least one optical fiber that enters through the input port can be split or otherwise separated from the remainder of the optical fibers and routed through the branch portion. To prevent the optical fibers that are routed through the branch portion from being bent excessively, the branch portion defines an acute angle, such as between about 20xc2x0 and 40xc2x0 and, more preferably, about 30xc2x0, with respect to the inline portion proximate the primary output port. The branch portion is also typically smaller in lateral cross-sectional area than the inline portion. In one embodiment, the branch portion includes a first segment proximate the inline portion that extends outwardly from the inline portion and that defines the acute angle with respect to the inline portion proximate the primary output port. Additionally, the branch portion of this embodiment includes a second segment connected to the first segment that extends parallel to the inline portion. The apparatus for splitting optical fibers of this aspect of the present invention can therefore separate one or more optical fibers from a plurality of optical fibers, while protecting the optical fibers that are being separated from being bent excessively or from being otherwise physically damaged.
According to another aspect of the present invention, a method is provided for splitting a plurality of optical fibers. According to this method, the splitter housing is separated in the first and second halves. A plurality of optical fibers are then routed through the opened splitter housing such that at least one optical fiber extends from the input port to the primary output port while another optical fiber extends from the input port to the secondary output port. The first and second halves of the splitter housing are then closed together to retain the plurality of optical fibers therein. Once closed, the first and second halves of the splitter housing are latched together in the closed position.
The plurality of optical fibers that exit through the secondary output port can also be split or otherwise separated. The separated optical fibers can then be directed through respective transport tubes that serve to further protect the optical fibers against physical damage. In embodiments in which an adapter element is disposed within the splitter housing proximate the input port, at least a portion of the fiber optic cable that provides the plurality of optical fibers can be secured to the adapter element. Thus, the splitter housing is capable of being mounted upon different types of fiber optic cables. Prior to closing the splitter housing, at least some of the optical fibers that exit through the secondary output port can also be engaged. As such, those optical fibers are retained within the splitter housing while the first and second halves of the splitter housing are being closed to prevent the optical fibers from being crushed between the first and second halves of the splitter housing.
The apparatus and method for splitting optical fibers according to the present invention therefore permit optical fibers to be selectively separated in a manner that protects the optical fibers by preventing the optical fibers from being excessively bent or from otherwise being physically damaged. In addition, the apparatus and method for splitting optical fibers according to the present invention can redirect the optical fibers without requiring all of the optical fibers to be cut. In particular, the express fibers can extend uninterrupted through the splitter housing without being cut. Moreover, the apparatus and method for splitting optical fibers according to the present invention can be utilized in conjunction with a wide variety of different types of fiber optic cables.